Mitral Stenosis

Physical Examination

General examination:

• Malar flush: redness over the cheeks suggesting reduced cardiac output

• Dyspnea: difficulty in breathing indicating poor oxygenation

• Orthopnea: shortness of breath while lying flat, suggesting left ventricular dysfunction

• Peripheral edema: swelling of the ankles or feet, indicating right heart failure

• Precordial inspection:

• Visible lift of the chest wall near the sternum, sign of right ventricular hypertrophy

• Palpation:

• Tapping apex beat: palpable first heart sound (S1) at the apex, indicating forceful closure of mitral valve

• Parasternal heave: palpable impulse over the lower left sternal edge due to right ventricular hypertrophy

• Left atrial enlargement: palpable double impulse at the apex, caused by the left atrial contraction and ventricular systole

• Auscultation:

• Loud first heart sound (S1): accentuated due to forceful closure of the mitral valve

• Opening snap: high-pitched diastolic sound after the second heart sound (S2), indicating abrupt halt of the opening mitral valve leaflets

• Mid-diastolic murmur: low-pitched rumbling sound heard at the apex, suggestive of blood flow across the stenotic mitral valve

• Presystolic accentuation: increased intensity of mid-diastolic murmur just before the first heart sound (S1), indicating atrial contraction

• Additional examination:

• Jugular venous pressure (JVP): elevated due to increased right atrial pressure from right heart failure

• Pulmonary auscultation: fine crackles at lung bases, suggesting pulmonary congestion

• Hepatojugular reflux: increased JVP on pressing over the liver, indicating right heart failure

• Lower limb examination: pitting edema, reflecting fluid retention secondary to right heart failure

Investigations

Laboratory tests:

• Complete blood count (CBC): to assess for anemia or infection

• Renal function tests: to evaluate kidney function, as heart failure can cause renal dysfunction

• Liver function tests: to assess hepatic function and congestion secondary to right heart failure

• B-type natriuretic peptide (BNP): elevated levels indicating heart failure

• Coagulation profile: to assess clotting factors before invasive procedures

• Blood cultures: to rule out infective endocarditis in patients with fever or other signs of infection

• Imaging studies:

• Chest X-ray: to evaluate for cardiomegaly, left atrial enlargement, and pulmonary congestion

• Echocardiography (transthoracic and/or transesophageal): to assess mitral valve anatomy, severity of stenosis, and left atrial size

  • Example: presence of thickened and calcified mitral valve leaflets with limited mobility

• Cardiac magnetic resonance imaging (MRI): for detailed evaluation of valve anatomy, function, and quantification of stenosis

• Invasive tests:

• Cardiac catheterization: to measure pressure gradients across the mitral valve and evaluate for concomitant coronary artery disease

• Electrophysiological study: to assess for atrial fibrillation or other arrhythmias associated with mitral stenosis

• Other tests:

• Electrocardiogram (ECG): to detect atrial fibrillation, left atrial enlargement, or right ventricular hypertrophy

• Exercise stress testing: to evaluate functional capacity and symptom severity during exertion

• Holter monitor: to assess for paroxysmal atrial fibrillation or other arrhythmias over a 24-48 hour period

Management

General Management:

• Consider referral to a cardiologist for ongoing management and monitoring of the condition.

• Educate patients on signs and symptoms of heart failure and when to seek medical attention.

• Encourage regular follow-up visits to monitor the progression of the disease and adjust treatment as needed.

• Assess the severity of mitral stenosis using echocardiography.

• Monitor for signs of heart failure, such as dyspnea, orthopnea, and peripheral edema.

• Encourage healthy lifestyle habits, such as regular exercise and a low-salt diet.

• Manage comorbid conditions, such as hypertension and diabetes, as appropriate.

• Consider anticoagulation therapy to prevent thromboembolism in patients with atrial fibrillation.

Medical Management:

• Diuretics may be used to manage fluid overload and symptoms of heart failure.

• Beta-blockers can help reduce heart rate and improve diastolic filling.

• Calcium channel blockers may also be used to reduce heart rate and improve diastolic filling.

• In patients with atrial fibrillation, consider anticoagulation therapy to prevent thromboembolism.

Surgical Management:

• Mitral valve repair or replacement may be considered in patients with severe symptoms or progressive disease.

• Percutaneous balloon mitral valvuloplasty may be an option for some patients, particularly those who are not good candidates for surgery

Causes of Mitral Stenosis

Congenital causes:

• Congenital mitral valve abnormalities

• Abnormal valve leaflets or subvalvular apparatus

• Mitral valve stenosis may also be associated with other congenital heart defects

Acquired causes:

• Rheumatic fever (most common worldwide)

• Mitral annular calcification

• Infective endocarditis leading to scarring and thickening of the valve leaflets

• Systemic lupus erythematosus and other autoimmune diseases

• Radiation therapy to the chest

• Carcinoid syndrome (rare)

• In rare cases, idiopathic calcification of the mitral valve.

Causes of Mid-Diastolic Murmur

• Mitral stenosis

• Atrial myxoma

• Tricuspid stenosis

• Austin-Flint murmur

Clinical Signs of Severe Mitral Stenosis

• The presence of atrial fibrillation (AF)

• Signs of pulmonary hypertension

• A short gap between S2 and the opening snap, as the left atrial pressure is very high in severe MS, and therefore the pressure gradient exceeds ventricular pressure earlier, so the valve opens earlier.

• A long mid-diastolic murmur, as the left atrial-left ventricular gradient takes longer to equalize with increasing severity of MS.

• Signs of pulmonary congestion and right heart failure, such as dyspnea, orthopnea, paroxysmal nocturnal dyspnea, fatigue, peripheral edema, elevated jugular venous pressure, hepatomegaly, and ascites.

Rheumatic Fever

Rheumatic fever is an inflammatory condition that can develop as a complication of untreated or inadequately treated streptococcal pharyngitis (strep throat) caused by group A streptococcus.

• Pathophysiology: Rheumatic fever is thought to be caused by an autoimmune reaction triggered by the streptococcal infection, leading to the formation of antibodies that cross-react with human tissues, including the heart, joints, and central nervous system.

• Clinical features: The clinical features of rheumatic fever can vary but typically include fever, joint pain and swelling (migratory polyarthritis), rash (erythema marginatum), subcutaneous nodules, and cardiac involvement, such as valvulitis, myocarditis, and pericarditis.

• Diagnosis: The diagnosis of rheumatic fever is based on the presence of two major criteria or one major and two minor criteria according to the modified Jones criteria. The major criteria include carditis, migratory polyarthritis, subcutaneous nodules, erythema marginatum, and Sydenham's chorea. The minor criteria include fever, arthralgia, elevated acute-phase reactants, prolonged PR interval on electrocardiogram, and evidence of recent streptococcal infection.

• Treatment: Treatment of rheumatic fever typically involves antibiotics to eradicate the streptococcal infection, as well as anti-inflammatory agents such as nonsteroidal anti-inflammatory drugs (NSAIDs) or corticosteroids to reduce inflammation and manage symptoms.

• Complications: Rheumatic fever can lead to long-term complications such as chronic rheumatic heart disease, which may cause valve damage and lead to heart failure, arrhythmias, and stroke.